class Solution {
public:
    int minDistance(string word1, string word2)
    {
        int m = word1.size(), n = word2.size();
        vector<vector<int>> dp(m + 1, vector<int>(n + 1));
        dp[0][0] = 0;
        for (int i = 1; i <= m; i++)dp[i][0] = i;
        for (int i = 1; i <= n; i++)dp[0][i] = i;

        for (int i = 1; i <= m; i++)
        {
            for (int j = 1; j <= n; j++)
            {
                dp[i][j] = min(dp[i - 1][j], dp[i][j - 1]) + 1;
                if (word1[i - 1] == word2[j - 1])
                {
                    dp[i][j] = min(dp[i][j], dp[i - 1][j - 1]);
                }
            }
        }

        return dp[m][n];
    }
};